Why am I getting separatism in this province?

[joos]

Playing as Portugal, I colonized Whydah, a West African province. As soon the colony completed, I saw that there was unrest despite being part of a trading company. And the main factor for the unrest was separatism. This screenshot was taken more than 10 years after I colonized it, and the separatism is still there. In fact, I recently had to use Harsh Treatment to suppress Dahomeian Separatists from rebelling.

Why am I getting separatism in what was a previously empty province? None of my other west African colonies have this. Does it have something to do with the specific culture in this province? No other country has or has ever had cores in this province.

 

[ShoGuL]

IIRC the nation in Kumasi spawns by event, it might give separatism in any same culture provinces?

But if I were to take a guess, I would say it's probably caused by an event. Were you above 100% overextension at any point? That's the most common cause.

Otherwise, I don't know

 

[Bouchart]

Take a look at the Province History button in the top left corner. There's probably a clue there.